3D flower-like molybdenum disulfide modified graphite felt as a positive material for vanadium redox flow batteries

3D flower-like molybdenum disulfide microsphere modified graphite felt (MoS₂/GF) with excellent electrocatalytic activity and redox reversibility for the VO²⁺/VO₂⁺couple is successfully fabricated by a facile hydrothermal method. The results show that the hydrothermal reaction time has a deep influence on the MoS₂structure; an open 3D flower-like MoS₂structure with a layer spacing of 0.63 nm is uniformly grafted on the GF surface for a reaction time of 36 h. With the presence of MoS₂, the total resistance (1.58 O) and charge transfer resistance (0.01 O) of MoS₂/GF-36 are smaller than that of the heat treated GF (2.04 O and 11.27 O, respectively), indicating that the electrode has better conductivity and more favorable electron transfer ability. As expected, a significant increase in the capacity and energy efficiency is obtained with the MoS₂/GF-36 electrode. These satisfactory results are attributed to the 3D flower-like structure on the surface of the electrode, which increases the contact area between the electrode and the electrolyte. More importantly, the MoS₂/GF electrode with excellent stability has great application prospect in vanadium redox flow batteries (VRFBs).